Complete the indicated task to unlock the corresponding costume.
For each of the 14 playable characters of Class 0, there are alternate costumes. Each unlock requires 30 killsight (red reticule on target) kills per character. You can see how many you have in the library entry.
Breed the indicated Chocobos to get the corresponding offspring.
Choose a character that has upgraded Dodging capabilities (for example, Ace) then intentionally fail a SO. As soon as you fail, keep dodging until you avoid three instant death circles.
Complete any non-real time strategy mission with only one cadet. After accepting the mission, refuse any assistance. No additional reserves are allowed.